Blood in the vomit last night?

I threw up last night after I'd been drinking and there was a lot of thick, clotted looking blood in it but I just went to bed. I feel ok this morning but there's a somewhat sharp pain on my lower right side stomach/back area and my stool is dark green. I've been having stomach problems for years and just recently started seeing a gastroenterologist who thinks I may have gastritis because my stomach lining was inflamed when he did an endoscopy. Should I go to the hospital if I haven't thrown up since last night? Was it just from the drinking?